Depression of cardiovascular autonomic function is more pronounced after mitral valve surgery: evidence for direct trauma

Abstract

The analysis of baroreflex sensitivity (BRS) and heart rate variability (HRV ) leads to additional insights into patients' prognosis after cardiovascular events. The following study was performed to assess the differences in the post-operative recovery of autonomic regulation after mitral valve (MV ) and aortic valve (AV ) surgery with a heart-lung machine. Among the 43 consecutive male patients enrolled in a prospective study, 26 underwent isolated AV surgery and 17 isolated MV surgery. Blood pressure as well as ECG signals were recorded the day before, 24 hours after and one week after surgery. BRS was calculated according to the dual sequence method, and HRV was calculated using standard linear as well as nonlinear parameters. There were no major differences between the two groups in the pre-operative values. At 24 hours a comparable depression of HRV and BRS in both groups was observed, while at 7 days there was partial recovery in AV patients, which was absent in MV patients: p (AV versus MV )!0.001. While the response of the autonomic system to surgery is similar in AV and MV patients, there is obviously a decreased ability to recover in MV patients, probably attributed to traumatic lesions of the autonomic nervous system by opening the atria. Ongoing research is required for further clarification of the pathophysiology of this phenomenon and to establish strategies to restore autonomic function.

Abnormal heart rate variability and atrial fibrillation after aortic surgery

“…In any manner, no significant reduction of incidence of AF (37% vs. 49%) was observed in the subgroup of patients from group B that also presented a similarly marked depression of HRV parameters. This observation could support the hypothesis that the possible protective factor against appearance of AF is not the level of postoperative depression of HRV parameters by itself (expression of the autonomic derangement usually present after cardiac surgery and attributable to a variety of mechanisms) [ 31 , 32 ] , but an advanced autonomic blockade obtained by extensive heart denervation (as after resection of ascending aorta). This situation somehow resembles the protective effect given by the marked denervation-dysautonomia that occurs after heart transplant.…”

Impact of type of intervention for aortic valve replacement on heart rate variability

“…Our group of patients recently submitted to surgical replacement of the aortic valve (SAVR) presented abnormal HRV parameters, compatible with the presence of cardiac dysautonomia, as it is already known to occur after cardiac surgery [8][9][10]12]. SDNN was reduced to values on average around 70 ms, that are much shorter than the values of around 120 ms reported in literature for normal adults of comparable age [19,20]; other HRV parameters presented also significant degrees of reduction (in comparison to the data reported by Bonnemeier et al [20], Student's t test for independent samples: for SDNN p = 0.0000, for SDNN Index p = 0.0001; for SDANN p = 0.0000).…”

“…A very limited number of papers reported that HRV decreases also in patients undergoing valvular heart surgery, and that cardiovascular autonomic dysfunction seems to be more pronounced and persisting for longer period after mitral valve surgery than aortic valve surgery [11,12].…”

Impact of cardiac surgery on the autonomic cardiovascular function

“…More details regarding the calculation of the used parameters and their informative value can be found in [17] and [16]. Retzlaff et al [12,13] applied some additional univariate features (selected HRV features and features related to the BPV) which, due to the uniformity of the results obtained by using those features compared to the selected ones, were not separately considered in this contribution.…”

“…We previously analyzed the patients undergoing the depicted interventions by means of their HRV, BPV, and BRS in pairwise settings, i.e., AVR vs MVR and AVR vs TAVI [12,13]. The present contribution pooled together and widened the mentioned studies in terms of implicated patients, applied methods, and finally drew conclusions.…”